An online user today is exposed to a plethora of media exposures, such as banner ads, email ads, display ads, organic and paid search results, amongst others. These media exposures can be configured to direct a user to a particular website. When the online user performs a converting act, such as making an online purchase, advertisers would like to know which of the various media exposures the user was exposed to were responsible for the user's converting act. Historically, the media exposure the user was last exposed to would get all of the credit for the conversion, while all other media exposures that the user was exposed to would get none. This attribution model is referred to as last click attribution.